This invention relates to an electroacoustic, cardiographic method for combining, to a singularity from a plurality of anatomical source sites, various heart-functionality parameter measurements.
In the context of electroacoustic cardiography it is generally desirable to produce measurements from more than one anatomical site, thus to provide an important measure of signal-gathering robustness relative to noise, and also to furnish good assurance that the resulting information will not depend too much on the particular conditions of signal gathering existing at but a single anatomical site. However, in order successfully to produce a single set of measurements to a clinician, measurements from such multiple anatomical sites must in some fashion be appropriately combined.
Accordingly, the present invention focuses attention on a unique method for combining such parameter measurements derived from multiple, captured events at more than one anatomical site.
In the context of electroacoustic cardiography, examples of plural-anatomical-site, event-wise measurements include, as just an illustration, the sequence of electromechanical activation times—EMAT—as measured during each cardiac cycle during which data is collected. Collected data to yield such a measurement includes, of course, both ECG information and heart-sound information. If appropriate electrical and acoustic sensors are located, for example, at two anatomical sites, then two separate sequences of EMAT measurements would be available, and such two measurements squarely present the issue of achieving an appropriate combination of these measurements so that a clinician will be working with useful EMAT measurement data as a singularity.
In terms of the practice of the present invention, other important heart-functionality parameters, in addition to the EMAT parameter, include LVST, PADT, and AAFT. Also in terms of the practice of the invention, and as will become apparent, the number of plural sites which can be handled is not limited to just two sites.
According to a preferred and best-mode manner of practicing the invention, a practice which involves uniquely algorithmically programmed, digital-computer data-processing, the steps of the invention may be expressed in the following sequence: (a) over a predetermined number of cardiac cycles, collecting ECG and heart-sound data, including plural-anatomical-site heart-sound data, relevant to the measurement of a selected, heart-functionality parameter, (b) computer processing such collected data to acquire per-site, per-cycle nominal measurement values for that parameter (such as for any one of the four, above-identified parameters; (c) relative to each anatomical site, computing the arithmetic mean of the nominal selected-parameter measurement values associated with that site by summing all of such site-associated nominal values and dividing that sum by the predetermined number of cycles; (d) also relative to each site, computing the variance of the associated nominal values by summing the squared difference between each such nominal value and the computed arithmetic mean, and dividing this squared-difference sum by the predetermined number of cycles; (e) computing weighted values for all of the nominal values that are associated with all of the plural anatomical sites by multiplying each such per-site value by a weight coefficient which is equal to the inverse of the variance that is associated with the value's associated anatomical site; (f) computing the weighted average of all of the nominal values that are associated with all of the plural anatomical sites by summing all of the weighted values and then dividing that weighted-value sum by the sum of all of the weight coefficients; and (g) presenting the computed weighted average as being the assessed, combined, singular value of the selected parameter.
These and other features and advantages which are offered by the present invention will become more fully apparent as the detailed description of the invention which shortly follows is read in conjunction with the accompanying single drawing FIGURE.